The AIIMS in Rishikesh where environmentalist G D Agarwal died after a 110-day fast to save the Ganga has threatened to file a defamation case against the ashram with which he was associated for accusing it of being a part of a conspiracy to kill the activist.

But the Matri Sadan ashram reiterated its charge Saturday, saying it would lodge an FIR over the conspiracy .

There is a tussle over IIT professor-turned-seer's body as well.

Agarwal's spiritual guru Swami Avimukteshwaranand has laid claim on it while the government hospital says the activist had pledged his organs for medical research at the institute.

G D Agarwal, also known as Swami Gyanswaroop Sanand, died at Rishikesh's All India Institute of Medical Sciences on Thursday, where he was forcibly brought a day earlier.

He was on an indefinite fast at Matri Sadan in Rishikesh, demanding government measures to ensure a clean, free-flowing Ganga.

AIIMS director Ravi Kant said the institute is all set to take the Rishikesh ashram to court over the conspiracy allegation.

"We have given the green signal to our legal team to go ahead and file a defamation suit against Matri Sadan for levelling an unfounded allegation like this against a premier medical institution like ours," he told PTI on Saturday.

But Maitri Sadan's head Shivanand reiterated the charge, telling PTI that the ashram planned to lodge an FIR against those involved in a conspiracy to kill Swami Gyanswaroop Sanand.

Shivanand also threatened to take the matter to court if nothing was done to resolve the alleged conspiracy which led to the clean Ganga activist's murder

He said he planned to sit on an indefinite fast for the cause of Ganga soon to take Swami Gyanswaroop Sanand's fight to its logical conclusion. The fast is likely to begin on October 20, he said

AIIMS director Ravi Kant said there was no question of the hospital handing over Agrawal's body to any other institution as the seer had himself donated it to the Department of Anatomy for medical education and research.

Swami Avimuketshwaranand had said Friday he will go to court to claim Agarwal's body as the seer was his disciple and the AIIMS had been part of a conspiracy to kill him.

Ravi Kant rubbished the conspiracy theory and claimed Agarwal was admitted twice at the institute during his fast and stayed there for about three weeks altogether.

The activist had continued his fast even in the hospital then.

Ravi Kant said Agarwal shared a special bond with the doctors attending on him and held the institution in high esteem.

There was a free-wheeling interaction with him during the hospital stay, he said.

It seemed continuing his indefinite fast was not just his individual decision," the hospital director said.

"He said things like how could he end it without the permission of the head of his institute (Matri Sadan), Ravi Kant claimed.